Use of Electromagnetic Foraging Cues By Conophagous Insects Tracy - - PowerPoint PPT Presentation

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Jan 15, 2024 373 likes •636 views

Use of Electromagnetic Foraging Cues By Conophagous Insects Tracy Zahradnik 1 Stephan Takcs 1 , Michelle Tsang 1 , Ward Strong 2 , Robb Bennett 2 , Gerhard Gries 1 1Simon Fraser University, Image: Skeptical Teacher 2British Columbia Ministry

SLIDE 1

Use of Electromagnetic Foraging Cues By Conophagous Insects

Tracy Zahradnik1 Stephan Takàcs1, Michelle Tsang1, Ward Strong2, Robb Bennett2, Gerhard Gries1

1Simon Fraser University, 2British Columbia Ministry of Forests and Range

Image: Skeptical Teacher

SLIDE 2

Seed Orchards and The Insects

Leptoglossus occidentalis: seed orchard

pest, both adults and nymphs eat conifer seeds, and are known to use Infrared radiation (IR) as a foraging cue

(Takàcs et al., 2009)

Photo: Christopher Porter 8.0°C 21.0°C 8 10 12 14 16 18 20

SLIDE 3

Seed Orchards and The Insects

Contarinia oregonensis: seed orchard

pest, midge, females oviposit on conifer cones and larvae eat the seed

Dioryctria pseudotsugella: moth, conifer

tree defoliator, larvae will eat cones

Photo: Dick Willapalens Photo: Dion Manastyrski

SLIDE 4

Field Trapping IR Experiments

5.9°C 20.3°C

C. oregonensis attack Douglas-fir in early

season when cones are receptive for fertilization and IR in cones is visible.

SLIDE 5

Field Trapping IR Experiments

Cold Hot

SLIDE 6

Field Trapping IR Experiments

8.1°C 38.3°C 10 20 30 8.1°C 38.3°C 10 20 30

Cold Hot

SLIDE 7

Field Trapping IR Experiments:

C. Oregonensis

35 24 78 54

Saanichton Kalmalka

Number of Contarinia oregonensis

Hot Traps Cold Traps

* * *

n = 20

p < 0.05

SLIDE 8

Field Trapping IR Experiments:

D. pseudotsugella

2 20 6

Mated Female Unmated Female Male

Number of Dioryctria pseudotsugella

Hot Traps Cold Traps

* *

n = 20

*

p < 0.05

SLIDE 9

Field Colour Preference:

C. oregonensis

1 2 3 4 5

SLIDE 10

Field Colour Preference:

C. oregonensis

1 2 3 4 5 6 7

1 2 3 4 5

Average Larvae per Cone

1 2 3 4 5

SLIDE 11

Electromagnetic Cues: Leptoglossus occidentalis

Photo: Christopher Porter

Findings from Takàcs et al. (2009) using similar

experiments showed a preference in L. occidentalis for hot IR stimuli in the field trials and bioassays.

Electroretinograms can give the electrical potential of

the eye indicating what an eye can see, not what an insect prefers.

LED Peak Amplitude 440nm

420 430 440 450 460

Wavelength (nm) Amplitude

SLIDE 12

Electroretinograms

Photo: Christopher Porter

SLIDE 13

Average Responses of Male and Female Leptoglossus to Various Wavelenghts

0.2 0.4 0.6 0.8 1 1.2

370 372 376 390 395 400 408 425 433 452 470 474 480 505 527 541 567 571 572 573 590 592 594 595 604 610 621 636 642 648

Wavelength (nm) Ratio of Peak Amplitude

UV Visible Light

SLIDE 14

Mapping of Female Eyes

0.2 0.4 0.6 0.8 1 390 433 474 505 527 572 592 621

Wavelength (nm)

Ratio of Response Amplitude

Dorsal Ventral Equitorial

n = 10

SLIDE 15

Mapping of the Male Eyes

0.2 0.4 0.6 0.8 1 390 433 474 505 527 572 592 621

Wavelength (nm)

Ratio of Response Amplitude

Dorsal Ventral Equitorial

n = 10

SLIDE 16

Colour Selection Experiment:

L. occidentalis

505nm peak LED Green

?

430nm peak LED Blue Glass Plate Glass Plate

SLIDE 17

Colour Selection Experiment:

L. occidentalis

17 9 3 11 Male Female Number of of Responders Blue Green

* *

p < 0.05

SLIDE 18

Colour + IR Choice Experiment

?

505nm peak LED Green 430nm peak LED Blue Glass Plate Glass Plate Mirror Mirror Hot IR Source Cold IR Source

SLIDE 19

Colour + IR Choice Experiment

?

505nm peak LED Green 430nm peak LED Blue Glass Plate Glass Plate Mirror Mirror Cold IR Source Hot IR Source

SLIDE 20

Colour + IR Selection Experiment

17 9 10 11 7 8 3 11 3 3 2 Male Female Male Female Male Female

Number of Responders

Blue Green Blue+Hot Green+Cold Blue+Cold Green+Hot

* *

p < 0.05

SLIDE 21

Colour + IR Selection Experiment

p < 0.05 p > 0.05 p < 0.05 p < 0.05 p > 0.05 p > 0.05

17 9 10 11 7 8 3 11 3 3 2 Male Female Male Female Male Female

Number of Responders

Blue Green Blue+Hot Green+Cold Blue+Cold Green+Hot

* * *

p < 0.05

SLIDE 22

Average Responses of Male and Female Leptoglossus to Various Wavelenghts

0.2 0.4 0.6 0.8 1 1.2

370 372 376 390 395 400 408 425 433 452 470 474 480 505 527 541 567 571 572 573 590 592 594 595 604 610 621 636 642 648

Wavelength (nm) Ratio of Peak Amplitude

UV Visible Light

SLIDE 23

Colour + UV Selection Experiment

430nm peak LED Blue

?

430nm peak LED Blue + 390nm peak LED UV Glass Plate Glass Plate

SLIDE 24

Colour + UV Selection Experiment

6 5 6 5

Male Female

Number of Responders

Blue+UV Blue

SLIDE 25

Acknowledgements

Forest Genetics Council of British Columbia British Columbia Ministry of Forest and Range Saanichton British Columbia Ministry of Forest and Range Kalmalka, Vernon CANFOR Seed Orchard, Sechelt Simon Fraser University Caroline Whitehouse Tamara Richardson Nicole TunBridge Audrey Labrie Jim Corrigan Patti Brown Tom Cowan Regine Gries